How To Screen Record - With Audio - On A Mac

1. Download the free "soundflower" audio plugin [click here to start download]

2. Once installed, open System Preferences and go to Sound
     - Change Output and Input to use Soundflower (2ch)

3. Open QuickTime Player, and start a new Screen Recording.

4. It should automatically choose the same audio source as what is set in System Preferences, but you can verify that it is using Soundflower too.

You can now just record full screen and then play the video in full screen. You can trim the first few seconds of the video off when you're done.  You should still hear the audio playing from your regular Mac speakers, but it's actually recording from the source and not from the mic, so you'll hear that the audio in the final video sounds just like the original.